Why is the engine warning light constantly on?
2 Answers
The reasons why the engine warning light stays on are: 1. Excessive carbon deposits inside the engine, leading to poor gasoline atomization, damaged oxygen sensors, or incomplete combustion of gases in the combustion chamber; 2. Damaged spark plugs in the engine, causing cylinder misfires and insufficient power; 3. Damage to components of the vehicle's exhaust system, such as oxygen sensors and the three-way catalytic converter, resulting in substandard vehicle emissions; 4. Overheating of coolant or oil temperature, in which case the vehicle should be pulled over, turned off, and allowed to cool down. If the engine warning light remains on, the owner can try restarting and turning off the vehicle three times in a row, or disconnect the negative terminal of the car battery for 30 seconds before reconnecting it, to check if it's a false fault of the engine. If the warning light persists after these attempts, it is necessary to visit a 4S shop or repair shop to have technicians read and clear the fault codes using diagnostic equipment.
The engine warning light coming on is indeed unsettling. I've experienced this situation before. When that little yellow light illuminates, it's often due to an issue with the emission system - most commonly an abnormal oxygen sensor signal, which monitors exhaust composition. Sometimes using substandard gasoline, especially from small gas stations, can trigger the warning light. Pay special attention to the coolant temperature sensor data, as a faulty one can cause the engine to misinterpret operating temperature. My recommendation is to first try disconnecting the negative battery terminal for five minutes to reset the ECU. If the light remains on, immediately connect an OBD scanner to read the trouble codes. Don't make the same mistake as Old Zhang who drove for half a month with the light on, ending up needing to replace three oxygen sensors.
